Is pink noise the new white noise? This is what seems to indicate an investigation carried out by experts from the department of neurology at Northwestern University Feinberg School of Medicine in Illinois (United States) in which pink noise was much more effective for memory than what is known as white noise .
What is white noise
According to the National Sleep Foundation , white noise is any constant and random sound – that masks other sounds – throughout the night that helps us sleep; thus, white noise could be the sound of a fan, an air purifier, ocean waves, rain … its spectrum is flat in frequency and does not have any special characteristics.
What is pink noise
Pink noise has less amplitude for high frequencies. The idea is that the sound decays as the frequency rises; that is, its spectral density is inversely proportional to frequency. Thus, an example of pink noise could be the sound of the rain that we have previously passed through a filter to gradually remove the high frequencies, making it a more balanced and natural sound.
Development of the experiment
The small study included 13 older adults with an average age of about 75 years old, who spent two consecutive nights in a sleep laboratory. During one of those nights, the participants heard pink noise through headphones (continuous sounds but progressively decaying at high frequencies). Their memory was assessed both nights through a bedtime test and another just after waking up the next day. The results revealed that not only did the pink noise help the volunteers sleep deeper, but that those who heard it had better memory than the control subjects.
The effectiveness of pink noise is time-based , explains lead researcher Phyllis Zee. Sound was manipulated through headphones when the subjects were in deep, slow sleep. According to the authors, despite the results, this is a small sample and more tests should be done to determine the long-term effects of using pink noise to increase memory and improve sleep.
The study has been published in the journal Frontiers in Human Neuroscience.
